Mesoporous silica nanoparticle-embedded lanthanide organic polyhedra for enhanced stability, luminescence and cell imaging

Abstract

We report here a simple but efficient “ship-in-a-bottle” synthetic strategy for increasing the stability and luminescence performance of LOPs by embedding them into mesoporous silica nanoparticles (MSNs). Three types of hybrid materials, i.e. Eu₈L₁₂@MSNs, Eu₈L₁₂@MSNs-NH₂ and Eu₈L₁₂@MSNs-biotin, have been prepared and characterized by FT-IR, TGA, SEM and TEM. Photo-optical measurements confirmed that the photoluminescence quantum yields in water have been greatly improved from 5.50% for pristine Eu₈L₁₂ to 44.04% for Eu₈L₁₂@MSNs-biotin, along with fast disassembly for the former and the optical performance has been maintained for the latter under acidic conditions (pH = 4). Moreover, compared to Eu₈L₁₂, Eu₈L₁₂@MSNs and Eu₈L₁₂@MSNs-NH₂, the biotin-modified hybrid material Eu₈L₁₂@MSNs-biotin has exhibited much enhanced fluorescence-imaging ability toward the MDA-MB-231 human breast cancer cells, with significantly reduced dosage of the complex. Our work provides a useful strategy for the functionalization of multinuclear lanthanide organic assemblies toward their biosocial applications.